Power transmission mechanism



'7 Sheets-Sheet 1 C, G. WENNERSTROM POWER TRANSMISSION MECHANISM FiledMay 26, 19157 June 11, 1940.

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QJWWW@ June l1, 1940. c. G. WENNERSTROM 2,204,521

POWER TRANSMISSION ,MECHANISM `7 sheets-sheet 2 Filed May 26, 1937 INU!!June ll, 1940. c. G. wENNERsTRoM POWER TRANSMISSION MECHANISM Filed May26, 1937 7 Sheets-Sheet 3 INVENTOR. @UZ G Zas/272, @21R/T0772 BY pATTORNEY.

June 11,` 1940. c. G. wENNERsTRoM 2,204,521

POWER TRANSMISSION MECHANISM Filed May 26, 1937 7 Sheets-Sheet 4ATTORNEY.

June 11, 1940- c. G. WENNERSTROM `2,204,521

POWER TRANSMISSION MECHANI SM .Filed May 26, 1937 7 Sheets-Shea*l 5 IC:-.I

I N VEN TOR.

A TTORNE Y.

c'. G. wENNERsTRoM POWER TRANSMISSION 'MECHANISM June 11, 1940.

Filed May 26. 1957 7 Sheets-Sheet 6 n 7 o JU June 1l, 1940- c. G.wENNERsTRoM 2,204,521

POWER TRANSMISS ION MECHANI SM Filed May 26, 1957 7 Shee'cs-Shee'rl 7INVENTOR.

C22-'PZ' 6.' M6702 67255712772,

A TTORNE Y.

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Patented une 11, 119140 yrrrrENrv N oil-rios `2,204,521 POWERTRANSMISSION MECHANISM Uarl G. Wennerstrom, Evanston, Ill., assignor toUniversal Gear Corporation, Indianapolis, Ind., a corporation ofDelaware Application May 26, 1937, Serial No. 144,819 11 claims. (C1.n192--2-151Y This invention relates to power transmission mechanism, moreparticularly for power driven valves and like devices in which tightseating of the valving is important while avoiding danger of 1.5damaging the meeting surfaces.

Among other objects, the invention aims to provide simplied and improvedmeans for this purpose desirably housed as a unit.

Other objects and advantages will beapparent 1.110 from the followingdescription taken together with the accompanying drawings, in which:

Figure 1 is a longitudinalfsectional view of the improved device, partsbeing shown in elevation; Figure lais a cross-section on the lineIaf-e-Ia Figure 2 is a plan view with a top portion removed;

Figure 3 is a planview somewhat similar to Fig. 2 but showing aninterior View of said top portion, on a somewhat larger scale;

Figure 4 is a cross-section taken on the line 4-4 of Fig. l;

Figure 5 is another view of switch mechanism shown in Fig. 3, showingthe switch in off" position;

Figure 6 is another view of the upper part of parts shown in Fig. llooking from the opposite direction; Figure '1 is an enlarged view ofthe overload switch mechanism;

Figure 8 is an enlarged View of the time interval switch mechanism;

Figure 9 is a side'elevational view of the switch mechanism of Fig. 8;Figurel 10 is a perspective view, on a somewhat reduced scale, of theswitch vmechanism of Figs.

8 and 9, looking from the opposite direction; and

Figures 11, l2 and 13 show various operative positions of this latterswitch mechanism.

m Referring to the illustrative construction shown in the drawings, theunitary mechanism may' include an electric motor indicateddiagrammatically at ID and having a driving shaft Il. Secured to themotor I0 is the casing I2 coni- .45 prising a plurality of sections, oneof which is is the bushing 2I which is keyed, as by the featherconnection 22, to rotate with the shaft II. Set screw 22a preventsrelative longitudinal movement `of the shaft and bushing. About thejbushing 2l is a two-part separable main clutch 5 indicated generally bythe numeral 23 and comprising a portion 24 which is splined as by thefeather connection 22D to rotate with the shaft and also to move axiallythereof against the force of a heavy coil spring 26 which tends to pressthe 10 clutch section 24 into engagement with the other clutch section21 of the main clutch 23 and t0 cause the interengageable jaws '28 ofthese clutch sections to lmesh for thepurpose of transmitting power fromthe motor to the clutch section 21. 15 The clutch portion 21 is keyed torotate the double eccentric 29 as by a feather connection 30 betweenthis eccentric and the stub shaft extension 3| on the hub 32 of theclutch portion 21. The stub or input shaft 3l has a bearing in a 120hollow member `35 next described,` to permit relative rotation of theseparts.

The double eccentric `29 is part of a speedchanging mechanism followingbroadly the disclosures of the Pitter Patent No. 1,543,791 in .25 whichthese eccentrics by their rotation vwith themotor shaft II, through theclutch mechanism just described, cause the recprocation of a series ofradially disposed plungers 33 and34. These `plungers pass throughslotsin the hollow 30 rotatable member 35 and into interengagementrespectively with a series 36, 31 of beveled teeth cut internally in apair of` annular rings 38, 39. These rings are keyed to a normallystationary cylindrical spider 40 which has a bearing 40a in .35 the wallof the casing section 2U, in which, however, it is'rotatable upontheoccurrence of certain conditions hereinafter described. y

The bearing for the spider 49 carries a casing partition 4I which iscentrally apertured to ac- ..40 `commoclate'an anti-friction bearing 42for the rotatable member 35, this member being made a unit, by the bolts43 with a hub 44 of the driven shaft 45 which has an anti-.frictionbearing 46 in the end wall 41 of the casing section 20 and 45constitutes the output shaft of the mechanism. The hollow member 35 alsoprovides a journal for the `hub 32 ofthe clutch portion 21, the hub 44also providing a` journal for the end of the 'stub shaft 3|. 50

Theplungers 33 and 34 thus constitute. reactive parts which, under theinfluence of rota,- tion of the input shaft 3|, react with the teeth ofthe internalA gear 40 to cause rotation of the output shaft 45.

the teeth and with them the spider to which they are keyed be heldsubstantially stationary to cause transmission of power tothe shaft 45.In order normally to maintain the spider4 40 thus against rotation, thehub 48 of the spider through which `the shaft passes is formed into aworm wheel 49 which meshes with a hollow worm 50 formed integrally witha transversely disposed worm shaft 5| carried by the casingsection 20as4 `best shown in Fig. 4. The teeth ofthe worm ,50, are so cut thatrotation of the worm wheel 49 will tend to move the worm shaft 5|.axially and so asv not to cause substantial rotation of the worm. Thusunless the worm shaft 5| can move axially the wormwheel 49 and with itthe spider k4l! are; locked against rotation.

The worm shaft 5| is normally maintained against axial movement in onedirection bythe anti-friction bearing 52 which it has with the bearing53 Vwhich ycarries the worm-shaft inthe casing section 20, and in theother direction cornpression coil spring 54 disposed within the hollowinterior of the worm-shaft and bottomed at one lend against the shaft topress it toward the thrust bearing 52 and at the other end bottomedagainst an anti-friction thrust bearing 55 carried by the bearingbushing 56 and gland awhich supports the free end ofthe worm-shaft 5|.By an adjustment screw 51 which passes through the bushing and gland,the bearing 55 may be moved inwardly of the shaftiurther to compress thespring 54 and thus increase the vresistance to .movement of theworm-shaft 5|, lock-nut 58k serving to secure the selected adjustment.

n When Ithe output shaft 45 encounters an overload, as for example whena valve (not shown) driven by the shaft 445 reaches the limitl of itsclosing movement, the increased resistance to turning of the shaft 45will be transmitted to the worm wheel 49 and will enhance the tendencyof this worm wheel to turn in clockwise direction,V looking at Fig. 4.As ,soon as this increased tendency of thev worm wheel 49 to rotate inthis direction overcomes the force of the spring 54, the worm-shaft 5|will move to the right in Fig. 4, permitting the worm wheel 49 to make aslight partial rotation. This in itself relieves the motor torque on theoutput shaft 45. Before this rotation has proceeded more than a .veryslight degree, however, the motor will be disconnected as presentlydescribed, positively relieving the motor torque on the worm wheel 49and causing the latter to be then brought to rest by limit of movementto the right of the worm-shaft 5|. Driven `shaft 45 also comes to restdue to the resistance encountered. The worm-shaft 5| at this time cannotmove back again to the left under the in- 'iiuence ofv the spring 54,for the reason that to do so it would have to rotate the worm wheel 49and with it the shaft 45, countercloekwise, against the resistance torotation of the shaft which is already greater thanthe force of thespring 54, as previously described.

Disconnecting ofthe motor, as just referred to,

will now be described. In its axial movement to the right in Fig. 4, theworm-shaft 5| moves the roller pin 59, which is disposed in an annulargroove in the shaft. This roller pin is carried by one end 6| (Fig. 2)of the lever Sla which is pivoted at 62 within the casing section 20.The other end 63 of this lever carries another pin 64 which forms abell-crank connection as by the link 65 with the slidable block 66carried by the stud 61 supported on the casing partition I5. The block56 has a yoke 58 which projects into the annular groove 5S in the clutchportion 24 of the main clutch 23. Thus when the worm-shaft 5| movesaxially to the right in Fig. Ll, the lever end 53 moves in a directionto straighten the link 65 and thus to' retract the clutch portion 24 andto place the clutch portions 24 and 21 out of engagement, disconnectingthe motor from the stub' shaft 3| and consequently from drivingconnection with the output shaft 45.

v'. llhelever end 63 also isY formed into a gear segment 10 whichengages with a pinion 1| fixed to the lower .end` of a switch shaft 12carried adjacent the lever end 03 by the upper casing portion 13.Movement of the lever end causes vrotation of the switch shaft 12 andwith it a cam member 14, Figs. 3 and 5, secured to shaft 12 by nut 14aby means of which relative rotative positions of the shaft and cam maybe adjusted. Thus, at the same time that the motor is disconnectednfromthe output shaft, the cam 14 is rotated to disconnect the current to themotor. Cam 714 has a fiat face 14h, which when in position asin Fig. 3,permits switch contact lever 14C pivoted at 14d to move under the.influence of a spring` 'rifle to close the overload switch 18 having theinsulated contacts 14j and 14g which (by suitable wiring, not shown) maybe normally in the motor circuit. As shown in Fig. 5, these contactshave been opened by action of the lever llila and cam 14. v

'At this time insulated contacts 93, 94 of anotheror time intervalswitch mechanism 92 are closed and in circuit with the motor, so that bymanually actuating an. operator controlled switch (not shown) `the motormay be energized for reverse or opening movement of the valve throughcontacts 93, 94. .Upon the actuation of such manually controlledswitch,"to open the valve, the motor begins to operate in a direction toopen the valve. Atthe beginning of such operation, as already described,the clutch 23 is disengaged. By reference to Figs.`1 and la, however, itwill be seen that within the hollow interior of the clutch Vportion21 ofthe main clutch 23 is an auxiliary one-way` clutch which transmits powerfrom the motor Vshaft to thev output shaft 45 independently of the mainvclutch 23 but only when the motor` is operating in a direction toy openthe `valve and while the main clutch '23 is disengaged. .l Thisauxiliary clutch, just referred to, comprises .thecup- |04 whichsurrounds the shaft end |81of the motor shaft A pair of rollers |05 vareloosely disposed in tapered recesses |06 in the sleeve 2| and uponrotation of the motor shaft ina direction to open `the valve (orclockwise, Fig-1a.), the rollers |05 tend to wedge themselves into thesmaller ends of the tapered recesses |06 and thusf-transmit'power fromthe motor shaft to cup |04. rIfhe cup |04 is centrally perforated toreceive therethrough the gland |01, the fhollowstem |01a of which isjournaled loosely inthe 'hub 32 of the clutch portion 21. A lightcompression coil spring |08 within this hollow shaft I8 and urges thegland |01 away fromthe portion of the gland which presses the cup |94between a pair of friction discs i953 and against the clutch portion 21,thus" providing a friction clutch which causes suicient rotation of thestub shaft 3l to .tend to rotate the shaft l5 clockwise (Fig. 4) whichrotates the worm wheel 49 in a counter-clockwise direction (looking atFig. 4) a sumcient `degree to move the worm 59 axially Iback to the leftto the position shown in Fig. 4;, whereupon further rotation of the wormwheel 49 is prevented by the worm.

Simultaneously with the axial movement of the worm 59 to the left (Fig.fi) as just described, the lever ends 6I and $3 move to the positionshown in Fig. 2, permitting the block 'to retracted under the influenceof the spring 26, whereupon the clutch portion 24 moves toward theclutch portion 21 to cause the jaws 28 to interengage and thus establisha positive power transmission means between the motor shaft H and thespeed reduction unit through the main clutch 23 which then transmits thepower tothe output shaft to open the valve. The auxiliary clutch isineffective during the remainder of the valve-opening operation andduring the succeeding valve-closing operation and until the main clutch23 is again disengaged by the over-load encountered b-y the shaft d5 atthe end of the next valve-closing operation. i i

Movementv of the lever end 83 to the position sho-wn in Fig. 2 alsoturns the shaft l2 ina direction to close the switch 18 so that bymanual operation of the operator controlled switch a circuit may belater established through the switch to close the valve. i

In order to shut off the motor at the end of the valve-opening rotationof the shaft, the switch mechanism 92 is provided `which is adapted tobe opened aftera given time interval. For the purpose just referred to,the periphery of the hollow rotatable member 35 is formed into a largeworm 19 which engages pinion 39 fixed to the switch shaft 92; The shaft92 is carried .by its upper end into the upper casing section 13. At theupper end of the shaft 82 is iixed a switch control mechanism comprisinganother worm 84 which engages a worm wheel 85 (Figs. 3 and 6) rigid witha counter-shaft 86. Counter-shaft 96 `is carried in suitable bearings86a., 89h and sleeve 86e carried by the casing section 13. To shaft 86is keyed a pair of discs 8l, 81a upon which ride a pawl 88 pivoted upona support 89, and having an extension Silbeyond its pivoted point towhich is secured the contact 93 of the switch 92 having the insulatedcontacts 93 and Si. Springs 96 urge the pawl 38 upon the periphery `ofthe `discs 81, Bla.` The discs 81, 91a which form a unitary caml for thepawl have jointly a peripheral cut 91 into which the pawl 98 drops(aided by the springs 96) when the discs 8l, 81a are -rotated by theshaft 86 to cause the slot to register` withthe pawl.A `This dropping'of `the pawl 8B raises the insulated contact 93 away from the contact 94to break the motor valve `opening circuit.

In order to cause a quick break in the circuit and avoid arcing, thefollowing mechanism is provided: The disc 81 is keyed by the pin 99 toturn with the counter-shaft 96, while the disc Sinds loose upon thiscounter-shaft and is driven by a pin ll fixed to the disc 81 andreceived in a slot 102 in the disc 81a as best shown in Fig. 9; The disc81 is of slightly larger diameter than the disc 81a and the pawl 88normally (that is, when the circuit is closed through this switch) rideson the periphery of the disc 8l. As the countershaft 86 rotatescounterclockwise (Fig. 9), the pin IIJ! travels in the same direction inthe slot HG2 until it drives the disc 81a. A spring 81h anchored at eachend to one of the discs Sl, 81d respectively tends to hold the pin lillagainst this end of the slot/|92 so that the right-angular face i990, ofthe disk 81a, is projected forwardly of the incline cut H19 of the disc91. Consequently as both discs now rotate together counterclockwise withthe counter-shaft 86 when the cut 91 arrives in the vicinity of thepawl, the pawl is momentarily supported by disc 81a and drops quicklyolf this disc, the right-angular face lllla permitting a quick drop andcircuit break by opening the switch 92, thus terminating thevalve-opening movement. i

`Upon actuation of the manually controlled switch to close the valve,the switch 18 now being closed,`the counter-shaft 86 now rotates in aclockwise direction and with it the disc 81. 'Ihe disc 81a. howevermomentarily cannot rotate in a clockwise direction because of the pawl8B. During this time the pin lill fixed on the disc 9i is traveling alsoclockwise in the slot lill against the action of the spring 81h which isplaced under tension. Before the pin reaches the limit of the slot 92 in`this direction, the inclined face |90 of the disc 81 has advancedsumciently (Fig. 12) of the face Imm` to` cam the pawl off of this faceMila and onto the periphery of the disci9l, which again closes the`switch 92. Thereupon the springilb rotates the disc back to a positionforwardly again of the inclined face N39 of the disc 81 `for the nextcycle of operation.

In order to vary the time interval for opening of the switch 92, thesupport 99 for the pawl 89 and the switch 92 are carried on .the annularmembers 99a., 89bwhich are bolted together and have a bearing on thesleeve 8650. of the shaft 86 but` are free with respect to the shaft.One of these membersilQh is in the form of a worm gear which meshes withaworrn 89C carried by the bracket 89d suitably mounted in the casingsection 13.' 4This worm is self-locking so that it prevents the members89a, 89h froml rotating. However, by inserting a screw-driver inthe kerf89e of the shaft of this worm 39o it .may be rotated 'to cause rotationof the members 89a, 99D to vary the location of the pawl with respect tothe peripheral cut 91 of the discs 81, 81a..

In addition to the improved mechanical opera,- tion of the heretoforedescribed mechanism, means are provided lfor hand operation of the shaftt5 to open or close the valve, and this provision will next bedescribed. The worm shaft 5l is extended exteriorly of the mechanismcasing as shown at IID and is adapted to `have a hand crankkeyedthereto.` While the teeth of the worm 59 are formed so thatrotation of the worm wheel 49 does not cause rotation of the worm 59,these teeth are so formed that rotation of the Worm shaft 5l causesrotation of the worm wheel 49 and thus the worm 5D is self-locking'inone direction but permits transmission of power by the shaft 5i to thespider 4U. l't` will be understood, for reasons already explained, thatwhen the spider 4l) rotates, the entire gear train comprising thespider, the plungers, the stub shaft 3l andtheoutput. shaft 45 `mayrotate as a unit. Also, if the clutch 23 should happen to be engaged atthe time of said hand operation, the motorshaft ll will also rotate as aunit with the'output shaft 45. For example, hand rotation of the spider40 counterclockwise will rotate the output shaft in the same directionto close the valve and conversely hand rotation of the spider 40clockwise will rotate the output shaft 45 in the latter direction toopen the valve, regardless of whether the motor is also connected ornot, the motor tending merely to accelerate or decelerate the handoperation. Thus, by

, means of the expedients described, hand operanot re-set by the spring54.

tion of the valve is always possible regardless of the relativepositions of the other parts of the mechanism. Furthermore, the motordrive is not through the worm 50, and the motor drive is Thus at alltimes the mechanism is and must be controlled by the operator with thedesirable exception` that an overload automatically disconnects andshuts off the motor. v

.It may sometimes be desirable to have the current shut off from themotor during closing movement of the valve after a time intervaL,independently of the overload cut-off mechanism just described, as forexample, for partial closing of the valve, and for this purpose theremay be provided another time interval switch mechanism similar to theswitch 92, and indicated diagrammatically at 200 in, place of the switch18.

The casing structure 2U is arranged so that the entire mechanismcontained in this end section of the casing may be operated in oil inthe usual Manifestly, the invention is not limited to details ofkconstruction shownfor purposes of illustration. Furthermore, it is notindispensable that all features of the invention be used conjointly, asvarious combinations and sub-combinations may be advantageouslyemployed.

Having described my invention, `I claim:

' 1. In power transmission mechanism ofthe class described, thecombination with a motor, of speed changing mechanism, anda jaw clutchbetween said motor and said speed changing mechanism wherein there is anauxiliary friction clutch operable upon rotation of the motor in onedirection only and during disengagement of the first mentioned clutch. l

2. In valve control power transmission mechanism of the class described,the combination with a motor, of speed changing mechanism including anormally stationary internal gear rotatable under predeterminedconditions, a positive jaw clutch between said motor and said speedchanging mechanism, and an auxiliary friction clutch transmitting powerwhen the jaw clutch is disengaged.

3. In power transmission mechanism, the combination with a source ofpower, of an out-put shaft having an enlarged hub, the combination of aworm integral with and of substantially the diameter of said hub, and arotatable switch control shaft having a Worm pinion in engagement withsaid worm.

4. The structure of claim 3 wherein. the switch control shaft has a wormthereon for driving a switch control countershaft.

5. The structure of claim 3 wherein the switch control shaft has a wormthereon for driving a switch control countershaft and wherein the switchcontrol countershaft drives a pair of cammed disks, one directly andanother by resilient means from the iirst disk for making and breakingthe circuit tothe source oi' power for said out-put shaft.

6. In valve control mechanism, the combination with a source of power,of speed reduction mechanism, a positive clutch therebetween,l meansincluding a normally stationary worm movable axially upon theencountering of an overload by said mechanism to disconnect the clutchpower, and an auxiliary friction clutch for transmitting the power whenthe positive clutch is disengaged and the power is applied to open theValve.

7. In power transmission mechanism of the class described, thecombination of speed changing mechanism including a normally stationaryinternal gear partially rotatable under predetermined conditions, anoutput shaft having a hollow hub received within the internal gear,slots in said hub, plungers in said slots, an input shaft having aportion within said hollow hub, eccentrics on said input shaft forreciprocating said plungers into and out of engagement with the teeth ofsaid internal gear, a worm wheel xed to said internal gear, aself-locking worm engaging said worm wheel whereby rotation of the wormrotates the worm wheel, gear, and output shaft, but rotation of the wormwheel does not substantially rotate the worm but moves the worm axially,and a spring resisting movement of the worm axially but permitting saidaxial movement upon the. encountering of a predetermined resistance torotation of the output shaft in a given direction whereupon the saidinternal gear rotates partially in an opposite direction. f

8. In power transmission mechanism of the class described, thecombination with a source of power, of an input shaft and an outputshaft, an

` internal gear and reactive parts adapted under the inuence of rotation'of said input shaft to react with said internal gear to cause rotationof said output shaft, a clutch between said source of power and saidinput shaft, a worm wheel fixed .on said internal gear, a worm meshingwith said worm wheel, said worm being movable axially by rotation ofsaid worm wheel upon the s encountering of a predetermined resistance torotation of said output shaft but said output shaft being adapted to bedriven by said input shaft independently of rotation kof said worm wheeland worm, a spring resisting said axial movement of the worm until saidpredetermined resistance is encountered, and means actuated by axialmovement of the worm for disconnecting said clutch.

9. In power transmission mechanism of the class described, thecombination with a source of power, of an input shaft'and an outputshaft, speed reducing mechanism including an internal gear and reactiveparts adaptedunder the iniiuence of rotation of said input shaft toreact with said internal gear to cause rotation of said output shaft ata reduced speed, a clutch between said source of power and said inputshaft, a worin wheel fixed on said internal gear, a worm meshing withsaid worm wheel, said worm being movable axially by rotation of saidworm wheel upon the encountering of a predetermined resistance torotation of said output shaft but said output shaft being adapted to beVdriven by said input shaft independently of rotation of said worm wheeland worm, a spring resisting said axial movement of the worm until saidpredetermined res-istance is encountered, means actuated by axialmovement of the worm both for disconnecting said clutch and for shuttingoff the power to said source, and means for rotating said? worm to causerotation of said gear and output shaft independently of said source ofpower. l

10. In power transmission mechanism of the class described, thecombination with a source of power, of input and output shafts, aninternal gear rotatable under predetermined conditions, reactive partsadapted under the inuence of rotation of said input shaft to react withsaid internal gear to cause rotation` `of said output shaft, a clutchbetween said source of power and said input shaft, a spring resistingrotation of said gear until a predetermined resistance to rotation ofsaid output shat is reached, and means actuated by rotation of said gearto come press said spring to disconnect said clutchi 11. In powertransmission mechanism of the. class described, the combination. with amotor, of speed changing mechanism including an internal gearcontinuously rotatable under `predetermined conditions and input andoutput shafts, said output shaft having a hollow hub received within theinternal gear, slots inrsaid liub, plungers in said slots, said inputshaft having a portion within said hollow hub, eccentrica on said inputshaft for reciprocating said plungers into and out of engagement with`said internal gear, a worm wheel fixed to said internal gear, a wormengaging said wormwheel whereby said output shaft is driven by saidsource of power independently of rotation of the internal gear butrotation` of the output shaft tends to cause rotation of the gear in adirection opposite to rotation of the output shaft, a spring resistingrotation of the gear in said direction,

`and means including said worm for causing rotation of the gear in thesame direction asv the output shaft to drive said output shaft.

CARL G. WENNERS'TROM.`

